Little Falls transcript. [volume] (Little Falls, Morrison County, Minn.) 1876-1894, 1887-03-25
HOW TO DIAKE<sI4ASS.
Tho Process or Manufacture Of the Dineren,
Kinds. g $$@5s.sz

G. Hansord Henderson, professor Of
chemistry and physics in the Indus
trial Training School, lectured at
Franklin Institute recentlyon "Glass
Making" After briefly retailing the
history of the art ofmaking glass, and
what glass was, Mr.. Henderson, said:
1.-THE operation of glass making re-
quires both skill and patience; nicely
in the mixture of the materials and
delicacy and dexterity in the manu-
facture OF the finished product. There
is no industry 50 benefited by tho
discovery Unnatural gas as this. Euro
pean manufacturers havelongused ar
tificial gas, it having been found that
smoke and sulphurous fumes from the
coal affected the clearness OF the pro-
duct. Where. in this country, nat
ural gas is not obtainedable. man.
ufactured gas is taking the place Of
coal in the principal furnaces. In the
furnace huge pots OF fire-clay, with
capacity Of 1,4o0 to 1000 pounds
of material, are filled with the
mixed substances called the BATCH
composed OF sand, lime and carbon
ate or sulphate OF soda in varying
proportions. lntQ a chamber beneath
them the burninggos streams. Above
each pot Is an ope :..g into the cham
Der in which it stands, through which
the blowpipe is dipped into it's con-
tents. The blowpipe is q heavy tube
OF wrought iron, it's loGer end some
what flanged.
In making the window-glass, the op-
orator repeatedly dips his pipe into
the molten glass, until on it's end is
mass Of fused glass. Whirling this
rapidly and dexterous!y it assumes a
pear-like shape. The opera =
blows into the pipe, mould
ing the huge bubble as it grows to the
size and shape of a carboy. The blow
ing now ceases, and the operator
swings his bubble in pit beneath his
platform, until by it's weight it length
ems into cylinder and cools to hard.
ness. The top and bottom OF this
cylinder are ingeniously got rid of,
and cold IRON Is run along one side
the remaining cylinder, making a
straight crack through its entire length.
1t is then put into an oven, crack up
permost, as it is heated it falls out in
to a flat plate and is ''ironed smo 9th"
by a fat piece OF wood on the end of
long bar. Lastly, it is put into the
annealine furnace, heated and allow
ed to cool very gradually, to tougher
the glass. It may then be cut up into
panes. Crown glass is made by gath
erlng the mass in the end of the pipe
blowing a. small bubble and transfer
ring it to an iron bar. The opening
left by the blowpipe is gradually en-.
larged as the mass is whirled until the
mass becomes CIRCULAR fiat disk. Its
disadvantages are it's variable thick
ness and the smallness OF the panes.
Plate glass is Of the same compost
tion as the former, but purer materi-
ais are used. It is cast on an iron or
bronze table from a huge ladle swung
rom the furnace to the table. Rollers
pass over it to secure uniform thick
ness. The result is a. rough slab, only
translucent. 1t is made smooth with
sand and emery, and polished with
burnt sulphate Of iron.
In making the batch for optical
glass lead is used instead of lime. This
branch Of the art reaches it's highest
perfection in America, and all the i'm
portant lenses for telescopes are made
| on this side Of the Atlantic. Another
fiat glass is seen in the car windows,
the design being pressed into the heat
ed pane, and the marks subsequently,
polished.
Mosaic glass is translucent, colored
unevenly by arsenic, tin and other
compounds, and is coming into use in
preference to stained glass, it's dura-
bility and richness OF shading being
superior to the latter.
1t is cast in small pieces, the opera.
tor himself not knowing exactly ow
the product will look, and the ARTS;
consequently can not have his pieces
made to order. A memorial window
in Milwaukee, made of this glass, the
subject being Christ Leaving the Hall
OF Justice contains goo figures.
Mr.. Yunk then mad. in miniature,
from glass tubes, some of the articles.
Briefly describing the process he said:
'Hollow-ware is either blown or press
ed. The furnace used in making it is
the Ferrari or tank furnace, the hot
air impinging on q constantly renewed
heap OF material in a reverberatory
chamber, the fused product flowing
away into tank, With openings above
it similar to those in other furnaces. By
this process work is kept up continu-
ously in blast from fall to spring. The
mass on the blow pipe is put into a
mould, which closes upon it while the
operator blows into it; the necks are
finished afterwards in an oxy-hydro.
gen flame. Finer holloware is mould
ed in the air entirely, it's surface being
rnuch brighter and smoother.
pressed glassware is made by pour
ing the motion glass into O. metal
mould, and another mould fitted to
its inside surface, pressed heavily into
It.. 1t is made in imitation OF cut
glass, but it distinguishable from it
by the dullness of it's edges, caused by
the product shrinking as it cools. Cut
glass, however, is now made from it.
the article being pressed into shape
and the design ground clear and sharp
with fine copper wire covered with
sand"